When enjoying a glass of wine, you may want to consider its cost when compared to the cost of a whole bottle.

Restaurants are naturally going to try to recoup the cost of the wine and make a profit. Zagat reports that at most restaurants, the price of a glass of wine is what they paid for the entire bottle wholesale.

There’s more: You wouldn’t eat someone else’s leftovers when you go out for a meal. Then why would you want to drink their leftover bottle of wine? That’s exactly what can happen, Zagat reports. Especially if someone else orders a bottle of wine and then decides that they don’t like it, some restaurants will serve it by the glass.

So Zagat advises that you order a whole bottle of wine. If you don’t finish it, ask the waiter whether you can take it home. Many restaurants will allow it.